Method of making heat-sealed and heat-shrunk package



Feb- 9, 1954 H. RUMsEY, JR 2,668,403

METHOD OF MAKING HEAT-SEALED AND HEAT-SHRUNK PACKAGE Filed Feb. 17, 1951I5 Sheets-Sheet l 3 INVENTOR. v 28 lf2 'hij 21a/15x95 BY .Y

r KAL Feb. 9, 1954 H. RuMsEY. .1R 2,668,403

METHOD OF MAKING HEAT-SEALED AND HEAT-,SHRUNK PACKAGE 3 Sheets-Sheet 2Filed Feb. 17. 1951 im ZKM /7 TTU/EWEY Feb. 9, 1954 H. RuMsEY, JR2,668,403

METHOD 0F' MAKING HEAT-*SEALED AND HEAT-SHRUNK PACKAGE '5 Sheets-Sheet 3Filed Feb. 17. 1951 41 INVENToR f6 isf/Zeri Fur/15e /ff MM f @L PatentedF eb. 9, 1954 METHOD OF MAKING HEAT-SEALED HEAT-SHRUNK PACKAGE ANDHerbert Rumsey, Jr., Rochester, N. Y. Application February 17, 1951,Serial No. 211,530

This invention relates to an improved heat sealed package and. to amethod of making the same.

My invention has particular relation to a package encased inthermoplastic sheet material and it isan object of the invention toprovide an improved package and method of this type wherein thethermoplastic sheet material is wrapped and secured around the packagein an improved tightly wrapped manner so as to present an attractiveappearance substantially free from wrinkles and irregularities.

My invention contemplates an improved package having a relatively stiisupport for protecting the package contents and providing the desiredcontour and shape tothe package and a wrapping of exible sheetmaterialwhich may be applied relatively loosely but is then shrunkaround the package so asto complete the assembly of the package andythen retain it in properly assembled relationship. The wrapping alsopresents a smooth finished appearance to the package.

My improved method and package are relatively inexpensive, do notrequire highly skilled or trained employees and result in an improvedattractive package in which the contents are effectively protected.

In the accompanying drawing- 4 Fig. 1 is a perspective View illustratingthe I'lrst step in carrying out my improved process;

Fig. 2 is a similar View of a further step; I

Fig. 3 is a perspective View showing the manner in which the package maybe placed on heat sealing apparatus for the heat sealing step;

Fig. 4 is a side elevational view illustrating the step of heat sealing;

Fig. 5 is a detailed view showing the engagement between the packagebeing wrapped and one of the heat sealing prongs of the apparatus shown-in Figs. 3 and 4;

Fig. 6 is a similar detailed view showing the manner in which thethermoplastic wrapping material of the package is heat sealed or fused;

Fig. 7 is a perspective view of a partially wrapped package which hasbeen heat sealed along one edge;

Fig. 8 is a similar view in which another edge of the wrapping materialhas Ibeen folded over and heat sealed;

' Fig. 9 is a similar view in'which the final edge has been folded overand heat sealed;

Fig. 10 is a perspective View illustrating the step in my processwherein the thermoplastic Wrapping material is heat shrunk around thePackage; Y f- .55. I8 is not essential and may beeliminated.

3 Claims. (Cl. 5310.5)

Fig. 11 is a view of the completed package with the thermoplasticwrapping material shrunk therearound so as to present a smooth,unwrinked appearance. s j

Fig. 12 is a. plan View of a blank for a supporting member which may beused in a modiiied form of package;

Fig. 13 is a perspective View of the supporting member after it has beenfolded around the package contents; l'

Fig. 14 is a perspective View similar to Fig. 13 illustrating the mannerin which a sheet of thermoplastic wrapping material may be wrappedthcrearound;

Fig. 15 is a perspective view'from the underside of the package with thethermoplastic wrapping material heat sealed around the package but priorto the shrinking of the lwrapping material;

Fig. 16. is a longitudinal sectional View in v'the direction of thearrows on line Iii- I6 of Fig. 15 ;V

Fig. 1'7 is a cross-sectional View in the direc*- tion of the arrowsonthe line l'l-l'l of Fig. 15

Fig. 18 is a perspective view of the completed package with thethermoplastic sheet material tightly shrunk around thepackage so astocomplete the assembly and retain it in position; and Fig. 19 is across-sectional View in the direction of the arrows onV the line lil- I9of Fig. 18. n d My invention is applicable to packages wrapped inthermoplastic sheet material and may be used in connection with packagesof Varying types and shapes. However, it has particular application torelatively ilat packages and to packages having a relatively stiffsupporting member or base and a flexible wrapping which is tightenedaround the package to complete the assembly and retain it in assembledrelationship and also to present a neat, nished appearance. Y In theaccompanying drawings I have illustrated my invention as applied to atpackages of this type having a supporting member or base. Thus, in Figs.1 to 11, I have illustrated a package l5 of shingled bacon disposed in asupport in the form of a relatively stiff member or base i6 made ofcardboard or other suitable material. The iiat base portion extendsVacross the bottom of the package and three integral flaps l1 extendupwardly and overlap theV face along three marginal edges. The outersurfaceof the support may have a coating I8 of thermoplastic materialsuch as wax, parain, thermoplastic resin orthe like having a lowermelting or fusingv point than the sheet wrapping material. How'- ever,it should be understood that `the coating In accordance with my methodthe support and its contents are wrapped in the manner hereinafterdescribed in a sheet I9 cf thermoplastic wrapping material. Thethermoplastic sheet inaterial may be of any known type such as celluloseacetate, or other cellulose esters, Pliolm or preferably a thermoplasticsheet material of the type which shrinks when heat is applied theretosuch as a polyvinyl film, specifically polyvinylidene chloride of thetype available commercially under the trade name of Saran. l

The rst step of my method may be carried out on a suitable station suchas platform 20. The package contents and support are placed facedownwardly on the sheet I9 of thermoplastic wrapping material on top ofplatform 2E and a relatively narrow strip of the wrapping material isfolded over the back of the package on the supporting member along onemarginal edge as shown at 2l. Thereafter, the sheet of thermoplasticwrapping material is drawn upwardly cn thev platform 20 and the entirepackage is folded over upon itself in the mannerl illustrated in Fig. 2.

It Will thus be seen that the thermoplastic wrapping material has beenwrapped around the package forming a tube ofY wrapping material open atboth ends of the package and with the wrapping material arranged inoverlapping relationship along one marginal area at the back of thepackage as shown at 2 I.

The next step in my method is to heat seal the overlapping marginaledges of the Wrapping material together and to sever the sheet wrappingmaterial along an edge of the package from the supply source. The heatsealing should preferably take the form of a plurality of proximatelypositioned heat sealed or fused points or spots extending along theoverlapping marginal areas inthe manner taught in my patent applicationSerial No. 37,978, filed July l0, 1948, for Package Encased in PlasticMaterial and Method of Making the Same, now Patent No. 2,545,243,granted October l0, 1950. v

VI prefer to accomplish the heat sealing and the severing of the web ofwrapping material from the source of supply by-means of a singleoperation in the manner taught in my copending application Serial No.198,107, lcd on November 29, 1950, for Apparatus for Heat Sealing andSevering Thermoplastic Materials,A now Patent No. 2,635,672, grantedApril 2l, 1953. Thus, as shown in Figs. 3, 4, and 5 the package l5 istransferred to another station taking the ferm of a hinged platform 22pivotally mounted at 23 and normally held in elevated or horizontalposition by means of a helical spring 24. The package is placed upon theplatform in upright position with the reinforcing backing i6 facingdownwardly and with the overlapping margins 2l positioned aboveapertures 25 formed in the platform. Beneath the respective apertures 25are a` plurality of heat sealing prongs 26 made of copper or othersuitable material and arranged in a row in alignment with the apertures.The prongs are suitably heated as by means of an electric heatingelement. When the left-hand end of the platform, as viewed in thedrawings, is depressed the prongs enter through the apertures 25 andengage the overlapping marginal portion of the Wrapping material. Theheat of the prongs is preferably controlled so that when they engage thethermoplastic Wrapping material they` cause the overlapping layers ofthe material to fuse at the points of contact thereby forming aplurality of apertures 2l through the layersv of material` as shown inFigs. 5 and 6. When the force is removed from the platform the spring 24returns it to horizontal position thereby withdrawing the engagement ofthe prongs from the wrapping material. The result is that the fusedthermoplastic material sets Vor hardens sealing the layers of wrappingmaterial together around the apertures as shown in Fig` 6.

The overlapping layers of material will thus be heat sealed or fusedtogether at a plurality of proximately positioned points throughout themarginal area. ff desired, the temperature of the prongs 26 may bemaintained at a level where they will not form apertures completelythrough the` thermoplastic sheet material but will only cause spotadhesions similar to spot welding. The control of the temperature may beaccomplished by thermostatic means or by reducing the diameter of theprongs or by making them of a material which is a less efficientconductor such` as ferrous metal rather than copper.

The prongs 26 are suitably supported so that they rest upon the copperplate 28 and heat from the plate will readily transfer to the prongs.The plate 28 has an upstanding flange 29 at the edge thereof forming aheat severing blade. The blade 2Q is maintained at a temperature wherebyit will fuse the thermoplastic material so that it can be readily heatsevered from the source of supply. The blade 2) is arranged so thatnormally it is cut of contact with the web of wrapping material as shownin Fig. 3. Thus, platform 22 has an upturned flange or edge 3G servingas a stop for positioning the package. The upper edge of the stop orflange 30 is positioned substantially above the upper edge of the blade29 when platform 22 is in elevated position. However, when the platformis depressed as shown in Figs. 4 and 5 the upper edge of flange 3G ispositioned beneath the upper edge of the heat severing blade with theresult that the heat severing blade engages the web of thermoplasticwrapping material and causes it to` be severed from its source ofsupply. Thus, in one operation the wrapping material is severed alongone edge of the package from its source of supply and the wrappingmaterial is spot welded or fused together in the marginal overlappingarea.

At this stage in my method the package is encased in a tube ofthermoplastic wrapping material as shown in Fig. 7 with the ends of theWrapping material in open condition and with the wrapping materialhaving an overlapping marginal area on the undersurface thereof. Thelayers of wrapping material in the overlapping area are spot welded orfused together at a. plurality of proximately positioned points.

In the illustrated embodiment the sheet Wrapping material is of such aWidth thatthe open ends project beyond the two sides of the package, asindicated at 3l and 32. When the Wrapping material is thus wider thanthe package the respective ends are folded inwardly against theundersurface of the package and heat sealed together in the same manneras the overlapping marginal band portion. Thus, as shown in Fig. 8, theend portion 3| is first turned under and the package is placed upon theplatform 22 with the inturned end 3l disposed upon the apertures 25. Theplatform is then depressed so that the heated prongs 26 engage theoverlapped ends of the material forming aI plurality of apertures 21which are heat sealed or fused around their marginal edges. The end 32is then turned inwardly against the undersurface of the package andthe-package is again positioned-on the platform 22 with the inturnedends 32 resting over the apertures 25 and the operation-is againrepeated. In this connection, it should be noted that the prongs 26 canpenetrate any desired number of layers of the thermoplastic sheetmaterial and in the marginal areas 3l and 32 a plurality of layers ofthe material are penetrated and fused together.

When all of the marginal areas have thus been heat fused or sealedtogether as shown in Fig. 9, it will be seen that the package is encasedin the thermoplastic wrapping. However, as indicated the thermoplasticwrapping vmaterial is not stretched tightly around the package and iswrinkled rather than smooth.' vWhere the sheet wrapping material is of acharacter which can be shrunk as, for instance, polyvinylidene chloridewhich can be heat shrunk, I then shrink the wrapping material around thepackage to provide a smooth, taut surface presenting an attractiveappearance free from wrinkles. The shrinking also serves to press thesupporting member tightly against the package contents and to hold thepackage in properly assembled relationship.

This may be accomplished in the manner indicated in Fig. by means of aheated plate The plate 33 is heated to a temperature which will causeshrinkage of the thermoplastic wrapping material but will not fuse ormelt the material. However, where the supporting member I6 has a coatingI8 of wax or thermoplastic resin, the temperature of the plate should besuch that it Will cause fusing or melting of the wax or similar coating.

In shrinking the material around the package I first piace the packageface downwardly on the plate 33 so that as the wrapping materialcontracts, the air inside the package can escape through the apertures2l. Thereafter, the back of the package is pressed downwardly on the hotplate 33 in the manner shown in Fig. 10 causing the shrinking of thewrapping material in that area and simultaneously melting or fusing thewax or other coating i8, where such a coating is employed. The meltingof the wax coating andits subsequent setting causes an adhesion, sealingcr fusing together of the wrapping material and the supporting member ofthe package with the result that the contents of the package areeffectively protected from undue exposure to the atmosphere.

The nished package as shown in Fig. 1 presents an attractive appearancewith the thermoplastic wrapping material tightly stretched in smoothrelationship around the package so as to retain it in properly assembledrelationship and so as to be substantially free from wrinkles. Theapertures 2i present spot fused or sealed spots in proximatelypositioned relationship along the overlapping marginal portions of thewrapping material. The adhesion between the waxed surface of thesupporting member l 6 and the wrapping material prevents undue exposureof the contents of the package to the atmosphere.

It should be noted that by making the package in the manner hereinillustrated and described a flap 34 is provided along the edge of thepackage immediately adjacent the overlapped margin 2l and parallel tothe side of the package. This ap forms a convenient tab that can begrasped in the hand and pulled for the purpose of opening the package.Also, due to the fact that the ap extends upwardly away from theoverlapped opened due to frictional engagement with protruding members.

In the modified package shown in Figs. 12 to 19 the Wrapping material isin the form of a tube wrapped around the package and open at both ends`It will be seen that I have provided a relatively stiff supportingmember 35 which serves to protect the package contents and to retain thepackage in relatively flatform. No coating need be applied to thesupporting memberk but may be if desired. The supporting member mayextend over one surface only of the package or as shown may extendcompletelyv around the package contents. Thus, I have il-V lustrated thesupporting member as having a base portion 35 with side naps 3l, a topportion 38 and an overlapping flap 39 for overlapping the bottom of thepackage. The top portion 38 may be provided with a suitable windowopening 40 through which the package contents are displayed.

The supporting member may be provided in blank form as shown in Fig. 12.The rst step in my method is to place the package contents upon theupper surface of the base portion 36 and to wrap the supporting memberaround the contents in the manner shown in Fig. 13 so that the flaps 31are folded inwardly over the ends of the package contents, the topportion 38 extends over the upper surface of the contents and the flap3Q is folded beneath the base portion 3S. Because the supporting memberis relatively stiff, it resists the folding action and the variouspanels and flaps ID tend to bulge outwardly as shown in Fig. 13.

Thereafter a sheet 42 of thermoplastic wrapping material of the typewhich can be shrunk around the package such as a polyvinyl nlm, par-`ticularly polyvinylidene chloride, is wrapped around the outside of thesupporting member in ie manner indicated in Figs. 14 and 15. The sheet42 should preferably be of a size to extend Y for substantially thelength of the package as l shown and so as to extend completely aroundthe package in tubular form with its ends in overlapping relationship.

The overlapping edges of the wrapping material are vpreferablypositioned on the undersurface of the pack-age as shown in Figs. 15 to19 adjacent flap 39. These edges are heat sealed in the mannerpreviously described in connection with the first form of my inventionso as to form aplurality of spots or apertures 43 extending through bothlayers of the thermoplastic material with the peripheral edges fused orsealed together.

As shown in Figs. l5, 16 and 17, after the sheet of wrapping materialhas thus been wrapped around the package and heat fused or sealed inposition it lits rather loosely and the flaps and panels of thesupporting member, because of the stiiness thereof, continue to bulgeoutwardly. Under those circumstances, the package does not present afinished appearance and the assembly of the supporting member around thepackage contents is not complete.

In order to complete the assembly of the package and present a finished,attractive appearance, I thereafter heat shrink the wrapping material 42around the package in the manner described in connection with the firstform of my invention. This may be accomplished by pressing the upper andlower surfaces of the package against a hot plate of the type shown inFig. 10.

The shrinking of the wrapping material around the package pulls theflaps and panels tightly into proper position and also eliminates thewrinkles and surplus material from the wrapping material as shown inFigs. 18 and 19. The nished package, as shown in Figs. 18 and 19, isheld in proper, assembled relationship by means or" the wrappingmaterial and presents a neat, attractive and nnished appearance.

It will thus be seen that I have provided an improved heat sealedpackage and method of making the same wherein a package of attractiveappearance affording protection to the contents thereof can he made in arelatively simple and lnexpensive manner. Modications may be made in theillustrated and described embodiment of my invention without departingfrom the invention as set forth in the accompanying claims.

I claim:

l. The method of making a package which comprises: placing packagecontents on a relatively stii supporting member having a coating ofthermoplastic material on the outer surface thereof; wrappingthermoplastic sheet material of the type which shrinks when subjected toheat and which has a higher melting point than the thermoplasticcoating, around the package contents and support with marginal areas ofthe sheet material arranged in overlapping relationship in contact withthe support; heat sealing the overlapping marginal areas of the sheetmaterial together; and subjecting the wrapped package to a temperaturelower than the melting point of the sheet material but higher than themelting point of the thermoplastic coating so as to shrink the sheetmaterial tightly around the package and so as to seal the wrappingmaterial to the support.

2. The method of making a package which comprises: placing packagecontents in relatively iiat form on a flat stiff supporting memberlhaving a thermoplastic coating on the outer surface thereof; thenwrapping thermoplastic sheet material of the type which shrinks whensubjected to heat and which has a higher melting point than thethermoplastic coating, around the package contents and support withmarginal areas in overlapping relationship in Contact with the support;next securing the marginal areas together by subjecting the sheetmaterial to heat higher than the melting point thereof at a plurality cfspaced points so as to form spaced apertures extending through theoverlapping layers of the sheet material with the edges of the materialaround the apertures fused together; and nally subjecting the wrappedpackage to a temperature lower than the melting point of the sheetmaterial but higher than the melting point of the thermoplastic coatingso as to shrink the sheet material tightly around the package and sealthe sheet material to the support.

3. The method of making a package which comprises: placing packagecontents on a relatively stiff supporting member having a coating ofthermoplastic material on the outer surface thereof; Wrappingthermoplastic sheet material of the type which shrinks when subjected toheat and which has a higher melting point than the thermoplastic coatingaround the package contents and support with marginal areas of thesheet; material arranged in overlapping relationship in contact With thesupport; securing the marginal areas of the sheet material together bysubjecting these areas of the sheet material to heat higher than themelting point thereof at a plurality of spaced points so as to formspaced apertures extending through the overlapping layers of sheetmaterial with the edges of the material around the apertures fusedtogether; subjecting the sheet material over the face of the package toan elevated temperature lower than the melting point thereof with theapertures in the marginal areas left unobstructed so as to shrink thesheet material over the face of the package and so that the air mayescape through the apertures; and finally subjecting the sheet materialover the supporting member to an elevated temperature lower than themelting point thereof but higher than the melting point of thethermoplastic coating so as to shrink the sheet material tightly overthe supporting member and seal the sheet material thereto.

HERBERT RUMSEY, JR.

References Cited in the ille of this patent UNITED STATES PATENTS NumberName Date 1,923,452 Neumillel Aug. 22, 1923 2,008,167 Bergstein July 16,1935 2,029,131 Shoemaker Jan. 28, 1936 2,131,699 ONeill et al. Sept. 27,1938 2,149,030 Moore Feb. 28, 1939 2,168,651 McCoy Aug. 8, 19392,179,504 Hasbrook Nov. 14, 1939 2,301,086 Snyder Nov. 3, 1942 2,331,794Mallory Oct. 12, 1943 2,518,711 Mulford Aug. l5, 1950 2,545,243 RumseyMar. 13, 1951

